The German patent according to DE 10 2007 040 605 B4 with the title “Apparatus for “in-situ” conveying of bitumen or very heavy oil”, grants protection to an apparatus with which thermal energy is applied to the oil sand deposit, referred to as reservoir, in order to reduce the viscosity of the bitumen or very heavy oil such that at least one electrical/electromagnetic heater is provided and an extraction pipe is present for leading away the liquefied bitumen or very heavy oil, wherein at least two linearly extended conductors are routed in parallel in the horizontal alignment at the predetermined depth of the reservoir, with the ends of the conductors being electrically conductively connected inside or outside of the reservoir and together forming a conductor loop, which realizes a predetermined complex resistance and are connected outside of the reservoir to an external alternating current generator for electrical power, with the inductivity of the conductor loop being compensated section by section. The reservoir can therefore be heated inductively.
The conveying method forming the basis of the above patent originates from the known SAGD (Steam Assisted Gravity Drainage) method. The SAGD method starts by both pipes typically being heated by steam for three months, in order to liquefy the bitumen in the space between the pipes at least as quickly as possible. Steam is subsequently introduced into the reservoir through the upper pipe and the conveying through the lower pipe can begin.
With older, non pre-published German patent applications from the applicant (DE 10 2007 008 192.6 with the title “Apparatus and method for “in-situ” extraction of a substance containing hydrocarbon by reducing its viscosity from a subterranean deposit” and DE 10 2007 036 832.3 with the title “Apparatus for “in-situ” extraction of a substance containing hydrocarbon”), electrical/electromagnetic heating methods are already proposed for an “in-situ” conveying of bitumen and/or very heavy oil, in which an inductive heating of the reservoir in particular takes place.
“In-situ” extraction methods of bitumen from oil sands using steam and horizontal bore holes (SAGD) are used commercially. To this end, large quantities of water vapor are needed in order to heat up the bitumen and large quantities of water to be cleaned accumulate. Reference has already made in such cases to the possibility of the steam-free subterranean heating of the bitumen. Purely electrically-resistive bitumen heating for conveying purposes is likewise known.